An air battery is a battery employing oxygen as a cathode active material; at the time of discharge, air is introduced from outside the battery. So, compared with other type of batteries which incorporate active materials for both cathode and anode, it is possible to enlarge the occupancy rate of the anode active material in the battery case. Hence, in principle, the air battery has features that dischargeable electric power is large as well as downsizing and weight saving can be easily carried out. In addition, oxidation power of oxygen to be employed as the cathode active material is strong so that the electromotive force is relatively high. Moreover, since oxygen is a clean resource the amount of which is not limited, the air battery is environmentally-friendly. As above, air battery has many advantages; therefore it is expected to be used for batteries for mobile devices, electric vehicles, hybrid cars, and fuel-cell-powered vehicle.
An embodiment of an air battery, for example, comprises: a housing; and a power section being incorporated in the housing, wherein the power section comprises, in the order mentioned: a cathode, an electrolyte layer including an electrolytic solution, and an anode. In this case, by ion conduction between the cathode and the anode through the electrolyte layer (electrolytic solution) of the power section, it is possible to take out the electric energy to outside the battery.
In the above embodiment employing an electrolytic solution in the electrolyte layer, problems such as depletion of the electrolytic solution and gas retention in the battery are caused due to, for example, volatilization of electrolytic solution as well as degradation of electrode material and electrolytic solution by the discharge. To solve the above problems, for instance, Patent literature 1 proposes an air battery where the air electrode and the anode are always filled with electrolytic solution by impregnating an entire power section with an electrolytic solution.